11.2 Movement Essential Idea: The roles of the musculoskeletal system are movement, support and protection.

http://www.wiley.com/college/pratt/0471393878/student/animations/actin_myosin/anim_text.html

By Darren Aherne

11.2 Movement: Essential Idea: The roles of the musculoskeletal system are movement, support and protection.

Assessment Statement Guidance

11.2 U1

Bones and exoskeletons provide anchorage for muscles and act as levers. Synovial joints allow certain movements but not others.

11.2 U2

Synovial joints allow certain movements but not others.

11.2 U3

Movement of the body requires muscles to work in antagonistic pairs.

11.2 U4

Skeletal muscle fibres are multinucleate and contain specialized endoplasmic reticulum.

11.2 U5

Muscle fibres contain many myofibrils.

11.2 U6

Each myofibril is made up of contractile sarcomeres.

11.2 U7

The contraction of the skeletal muscle is achieved by the sliding of actin and myosin filaments.

11.2 Movement: Essential Idea: The roles of the musculoskeletal system are movement, support and protection.

Assessment Statement Guidance

11.2 U8

ATP hydrolysis and cross bridge formation are necessary for the filaments to slide.

11.2 U9

Calcium ions and the proteins tropomyosin and troponin control muscle contractions.

11.2 A1

Application: Antagonistic pairs of muscles in an insect leg.

11.2 A2

Skill: Annotation of a diagram of the human elbow.

Elbow diagram should include cartilage, synovial fluid, joint capsule, named bones and named antagonistic muscles.

11.2 A3

Skill: Drawing labelled diagrams of the structure of a sarcomere.

Drawing labelled diagrams of the structure of a sarcomere should include Z lines, actin filaments, myosin filaments with heads, and the resultant light and dark bands.

11.2 A4

Skill: Analysis of electron micrographs to find the state of contraction of muscle fibres.

Measurement of the length of sarcomeres will require calibration of the eyepiece scale of the microscope.

11.2 U1 Bones and exoskeletons provide anchorage for muscles and act as levers. Synovial joints allow certain movements but not others.

Exoskeleton: hard, protective skeleton on the outside surface of the body- example: crab, cockroach Endoskeleton: skeleton on the inside of the body- example: dogs, humans Skeletons allow movement by providing attachment sites for muscles and working as levers. Levers change the size and direction of forces.

E= effort force, F= fulcrum, R= resultant force

From Biology Course Companion, Allott & Mindorf,, Oxford University Press, 2014, p. 477

11.2 A1 Application: Antagonistic pairs of muscles in an insect leg.

Insect legs also have antagonistic muscles to flex and extend the joint. femur

tibia

http://idtools.org/id/grasshoppers/images/fs_images/M_bruneri_leg_o.jpg

Jumping Action:

1. Extensor muscles relaxed 2. Flexor muscles in femur contract

making leg look Z shaped 3. Extensor muscles contract strongly,

causing tibia to extend, making insect jump

flex extend

From Biology Course Companion, Allott & Mindorf,, Oxford University Press, 2014, p. 478

11.2 U3 Movement of the body requires muscles to work in antagonistic pairs.

Muscles can only contract- i.e. pull by getting shorter. Muscles cross joints, and work together in antagonistic pairs- one pulls a joint one direction and its antagonist pulls it in the opposite direction- example biceps and triceps flex and extend the elbow joint.

Joint: the place where two bones meet Cartilage: tough smooth tissue that reduces friction & absorbs shocks Synovial fluid: lubricates the joint & fills the Joint Capsule: seals joint & keeps synovial fluid

From Biology Course Companion, Allott & Mindorf,, Oxford University Press, 2014, p. 478

11.2 U2 Synovial joints allow certain movements but not others.

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11.2 U4 Skeletal muscle fibers are multinucleate and contain specialized endoplasmic reticulum. 11.2 U5 Muscle fibers contain many myofibrils.

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11.2 U6 Each myofibril is made up of contractile sarcomeres.

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11.2 A3 Skill: Drawing labelled diagrams of the structure of a sarcomere.

Draw and label the structure of a sarcomere. (4 marks)

Include: Z lines, actin filaments, myosin filaments with heads, and the resultant light and dark bands Tips: • Indicate the sarcomere is between two Z

lines • Actin filaments connected to Z lines • Light bands labelled around the Z lines • Length of dark bands should be indicated

with arrows.

Sample mark scheme for a 4 mark question. Award [1] for each structure clearly drawn and correctly labelled. Sarcomere — clearly indicated between Z lines; Z lines; actin filaments attached to Z line; myosin filaments with heads; (two) light bands; dark band;

Draw and label the structure of a sarcomere. (4 marks)

From Biology Course Companion, Allott & Mindorf,, Oxford University Press, 2014, p. 481

11.2 U7 The contraction of the skeletal muscle is achieved by the sliding of actin and myosin filaments.

http://bcs.whfreeman.com/thelifewire/content/chp47/4702001.html

http://brookscole.cengage.com/chemistry_d/templates/student_resources/shared_resources/animations/muscles/muscles.html

i-biology.net

11.2 U8 ATP hydrolysis and cross bridge formation are necessary for the filaments to slide.

i-biology.net http://www.wiley.com/college/pratt/0471393878/student/animations/actin_myosin/actin_myosin.swf

11.2 U9 Calcium ions and the proteins tropomyosin and troponin control muscle contractions.

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11.2 A4 Skill: Analysis of electron micrographs to find the state of contraction of muscle fibres.

i-biology.net